The presence of numbness in the left side of the body in young people is considered to be caused by acute cerebrovascular disease. Young people may have insufficient risk factors for cerebral atherosclerosis, but young people may have congenital abnormal vascular development and sudden ischemia, which may also lead to the occurrence of cerebral infarction. Or because there is an aneurysm in the brain, the rupture of the aneurysm may cause cerebral hemorrhage, which may also lead to the sudden onset of numbness in the left side of the body of young people. Patients must consult a hospital in time to have a CT examination of the head to determine whether it is a hemorrhage or an infarction, and then give symptomatic treatment. Later, risk factors for cerebrovascular disease can be investigated, such as checking the blood vessels in the brain and doing angiography imaging of the head. It is also necessary to investigate rheumatological and immunological problems to see if this is the cause of the acute cerebrovascular disease.